I can tug you can tug she can tug we can tug you can tug they can tug
V-ing form
I can be tugging you can be tugging she can be tugging we can be tugging you can be tugging they can be tugging
Perfect
I can have tugged you can have tugged she can have tugged we can have tugged you can have tugged they can have tugged
V-ing perfect
I can have been tugging you can have been tugging she can have been tugging we can have been tugging you can have been tugging they can have been tugging
Negation
Simple form
I cannot tug you cannot tug she cannot tug we cannot tug you cannot tug they cannot tug
V-ing form
I cannot be tugging you cannot be tugging she cannot be tugging we cannot be tugging you cannot be tugging they cannot be tugging
Perfect
I cannot have tugged you cannot have tugged she cannot have tugged we cannot have tugged you cannot have tugged they cannot have tugged
V-ing perfect
I cannot have been tugging you cannot have been tugging she cannot have been tugging we cannot have been tugging you cannot have been tugging they cannot have been tugging
Interrogative form
Simple form
can I tug? can you tug? can she tug? can we tug? can you tug? can they tug?
V-ing form
can I be tugging? can you be tugging? can she be tugging? can we be tugging? can you be tugging? can they be tugging?
Perfect
can I have tugged? can you have tugged? can she have tugged? can we have tugged? can you have tugged? can they have tugged?
V-ing perfect
can I have been tugging? can you have been tugging? can she have been tugging? can we have been tugging? can you have been tugging? can they have been tugging?
Interro-negative form
Simple form
can I not tug? can you not tug? can she not tug? can we not tug? can you not tug? can they not tug?
V-ing form
can I not be tugging? can you not be tugging? can she not be tugging? can we not be tugging? can you not be tugging? can they not be tugging?
Perfect
can I not have tugged? can you not have tugged? can she not have tugged? can we not have tugged? can you not have tugged? can they not have tugged?
V-ing perfect
can I not have been tugging? can you not have been tugging? can she not have been tugging? can we not have been tugging? can you not have been tugging? can they not have been tugging?